This project will develop an in-depth understanding of early life mortality (ages 0-24) in the United States in the context of substantial racial/ethnic inequality and very rapid socioeconomic and family changes that have occurred in recent decades. Aims: We will document the associations between the risk of overall and cause-specific early life mortality with: parental socioeconomic status (SES), family structure, and race/ethnicity. We will do so for demographic subpopulations, for the contemporary time period and with regard to changes over the past 25 years, and for geographic areas of the country. Significance: Alarmingly, the United States ranks dead last in comparison to 16 high-income counterparts, usually by a sizeable margin, in age-specific early life mortality rates. Our proposed research is highly significant because it focuses on a crucial public health problem, addresses major gaps in knowledge regarding basic yet critical contemporary patterns of early life mortality, increases our limited knowledge about how trends of US early life mortality have unfolded over the last 25 years, and informs theoretical debates about changing patterns of mortality in an increasingly stratified society. Innovation: The project is highly innovative because it grounds the work in a conceptual framework that highlights the diverging socioeconomic and family contexts in which infants, children, and youth are living; devotes serious attention to the changing racial/ethnic composition of the population; and attend to both geographic variations and temporal trends. Framework: Our conceptual framework focuses on three interrelated resources-SES, family structure, and race/ethnicity-that are important in differentiating the survival prospects of individuals. Children living with the most highly educate parents are now supported by more economic and parental time resources than ever before while children living with the least educated parents lag further behind their counterparts than they did in the 1970s. Family structure changes are associated with and may be exacerbating these educational differences in children's resources. Such social and economic changes and continued racial/ethnic inequality may have pronounced effects on early life mortality risks, with particularly detrimental consequences for the most disadvantaged demographic subgroups living in the most disadvantaged geographic contexts. Data and Methods: We will primarily employ demographic methods and hazards modeling to exploit the two largest and most comprehensive US data sets extant for analyzing early life mortality: the 2013 release of the 1986-2011 National Health Interview Survey-Linked Mortality Files and the 1989-2008 NCHS Linked Cohort Birth/Infant Death Files. Conclusion: This project has enormous potential to produce new and important substantive and policy-relevant information about US early life mortality, a critical but woefully overlooked area of study. Ultimately, we expect to identify ways for US early life survival rates to match if not surpass rates for other high income countries.